BIOL1027 Final

Fall 2023 - Auburn University - Zanzot

Commonalities of All Living Organisms

Evolution, order/organization, reproduction, growth and development, energy processing, internal regulation, response to the environment

Levels of Life

Biosphere, Ecosystems, Communities, Populations, Organisms, Organ Systems, Organs, Tissues, Cells, Organelles, Molecules, Atoms

Taxa of Life

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Central Theory of Biology

Evolution by means of natural selection

Scientific Method

Observation, Hypothesis, Experiment, Data collection, and Conclusions

Matter

A substance that takes up space, has mass, is comprised of elements, and can exist as a solid, liquid, gas or plasma.

Important Elements for Life

Oxygen, Carbon, Hydrogen, and Nitrogen

Atomic Number

Number of protons in an element

Atomic Mass

Number of protons and neutrons in an element

Subatomic Particles

Proton, Neutron, Electron

Isotope

Same element, but a different number of neutrons and a different mass

Covalent Bonds

form when atoms share electrons to achieve stability.

Polar Covalent Bonds

occur when two atoms share electrons unequally due to a difference in electronegativity.

Ionic Bonds

form between atoms with different electronegativities.

Hydrogen Bonds

occur when atoms share electrons unevenly due to a difference in electronegativity, creating a dipole moment.

Van der Waals Interactions

weak attractive forces between molecules or atoms. They occur because of temporary fluctuations in electron distribution, creating temporary dipoles.

Dynamic Equilibrium

a state in which the forward and reverse processes occur at equal rates, resulting in a constant concentration of reactants and products.

Properties of Water that Contribute to Earth’s Suitability for Life

Ice floats, surface tension, specific heat, solvent.

High pH

Basic, OH^-

Low pH

Acid, H⁺

Buffer

Minimizes changes in pH, weakly ionizing

Mechanism

Living chemistry is complex, but reproducible. Molecules from living organisms can be reproduces from non-living sources.

Vitalism

Living molecules only come from living sources. There is a “living force” found only within organisms that are alive, which is surrendered at death.

Structural Isomers

Different covalent arrangements of their atoms

Cis-trans Isomers

Same covalent bonds but differ in spatial arrangements

Enantiomers

Isomers that are mirror images of each other

Functional Groups

The components of organic molecules that are most commonly involved in chemical reactions

OH

Hydroxyl

COOH

Carboxyl

C=O

Carbonyl

-SH

Sulfhydryl

-NH₂

Amino

-PO_4^2-

Phosphate

CH₃

Methyl

Macromolecules

Polymers built from monomers; formed by dehydration synthesis, broken down by hydrolysis

Carbohydrates

Sugars and polymers of sugars

Monomers

Single parts of repeating units that serve as building blocks

Polysaccharides

Polymers of sugars with storage and structural roles

Lipids

Not true polymers; hydrophobic; fats, phospholipids, steroids

Fat

Glycerol (3 carbon alcohol with hydroxyl group) and fatty acid (carboxyl group with carbon skeleton)

Steriods

Lipids characterized by a carbon skeleton consisting of four fused rings.

Proteins

More than 50% of the dry mass of most cells; functions include structural support, storage, transport, cellular communications, movement, and defense against foreign substances.

Amino Acid Structure

Amino group + alpha-carbon + carboxyl + R-group

Primary structure

Unique sequence of amino acids

Secondary Structure

Coils and folds in the polypeptide chain

Tertiary structure

Interactions among various side chains (R-group)

Quaternary structure

Consists of multiple polypeptide chains

Nucleic Acids

Store, transmit, and express hereditary information

Types of Nucleic Acids

RNA and DNA

Nucleotides

nitrogenous base + pentose sugar + phosphate group

Purines

A + G

Pyrimidines

C + T + U

Compound Light Microscope

Visible light is passed through a specimen and then through glass lenses

Transmission-Electron Microscope

Focuses a beam of electrons through a specimen

Scanning Electron Microscope

Focuses a beam of electrons onto the surface of a specimen, providing an image that looks 3D

Cell Fractionation

Takes cells apart and separates the major organelles from one another.

Prokaryotic Cells

Bacteria and Archaea; No nucleus, no membrane-bound organelles

Eukaryotic Cells

Fungi, Animals, Plants, and Protists; Cytoskeleton, Membrane-bound organelles, DNA in a nucleus.

Nuclear Envelope

A double membrane that encloses the nucleus, separating from the cytoplasm.

Ribosomes

Particles made of ribosomal RNA and protein. Carry out protein synthesis.

Rough ER

Surface studded with ribosomes; distributes transport vesicles, is a membrane factory for the cell.

Smooth ER

Synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, and stores calcium ions.

Golgi Apparatus

Modifies products of the ER, manufactures certain macromolecules, sorts and packages materials into transport vesicles.

Transport Vesicles

Proteins surrounded by membranes

Lysosome

A membranous sac of hydrolytic enzymes that can digest macromolecules.

Vacuoles

Food vacuoles, Contractile vacuoles, and Central vacuoles.

Endosymbiont Theory

An early ancestor of eukaryotic cells engulfed a non-photosynthetic prokaryotic cell, which formed an endosymbiont relationship with its host.

Mitochondria

Cristae, matrix, inner-membrane space; home of Krebs cycle and oxidative phosphorylation.

Chloroplasts

Contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis.

Granum

Stacks of thylakoids in the chloroplast

Structural Members of Cytoskeleton

Microtubules, Microfilaments, Intermediate filaments

Microtubules

Thickest of the three components; Cell motility, chromosome movements, organelle movements.

Microfilaments

Actin filaments, thinnest components; Cell motility, cell shape, cell division.

Intermediate filaments

Middle range components; Anchorage of nucleus, formation of nuclear lamina.

Intercellular Junctions

Desmosomes, tight junctions, gap junctions, plasmodesmata.

Desmosomes / Anchoring Junctions

Fasten cells together into strong sheets

Tight Junctions

Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid.

Gap Junctions / Communicating Junctions

Provide cytoplasmic channels between adjacent cells.

Plasmodesmata

Channels that perforate plant cell walls.

Extra Cellular Matrix

ECM proteins bind to receptor proteins in the plasma membrane called integrins

Fluid Mosaic Model

A membrane is a fluid structure with a “mosaic” of various proteins embedded in it.

Selective permeability

Small, non-polar molecules can pass through phospholipid bilayer

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water.

Isotonic Solution

No net water movement across the plasma membrane

Hypertonic Solution

Cell loses water

Hypotonic Solution

Cell gains water

Passive transport

Diffusion of a substance across a membrane with no energy investment

Active transport

Uses energy to move solutes against their gradients.

Bulk transport

Large molecules cross the membrane via vesicles

Exocytosis

Transport vesicles migrate to the membrane, fuse with it, and release their contents

Types of Endocytosis

Phagocytosis, pinocytosis, receptor-mediated endocytosis

Phagocytosis

Cellular eating

Pinocytosis

Cellular drinking

Receptor-mediated endocytosis

Ligand joins a receptor to signal coat proteins to start endocytosis.

1st Law of Thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed.

2nd Law of Thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

Metabolism

The totality of an organism’s chemical reactions

Anabolism

Consume energy to build complex molecules from simpler ones.

Catabolism

Release energy by breaking down complex molecules into simpler compounds.

Gibbs free energy

Energy that can do work when temperature and pressure are uniform, as in a living cell.